Function
Returns a sequence containing the elements of the stream up to, and including, the first occurrence of a given element.
read-through input-stream element #key on-end-of-stream test
=> sequence-or-eof found?
<stream>.
<object>.
<object>.
<function>. Default value: ==.
<sequence>, or an instance of <object> if the end of the stream is reached.
<boolean>.
io
streams
This function is the same as read-to, except that element is included in the resulting sequence.
If the element is not found, the result does not contain it. The stream is left positioned after element.